For heavy-duty stapling jobs such as insulation, carpet underlayment, and roofing felt

For use in Stanley model No

TRA60, TR85, TR100, TR150, TR150HL, TR250H, TRE550, TRE200, TRE500, and PHT150, Arrow model No

T-50, T-55, T-55C, ET-50, ETC-50, ETF-50, ETN-50, and HT-50A